Modeling a Radiator Heater
First I created this profile shape and extruded it to create the vertical pipes (CTRL + E) in Edit Mode.



Then added some loop cuts and joined them for the top, middle and bottom cross sections. Added a Subserf Modifier and some additional loop cuts to clean up some edges.

Then added an Array Modifier above the Subserf Modifier and applied it.

Then extruded the feet on the two ends and modeled the pipe to the floor.